How the world is once again out of balance in Korra's time.

When the world is thrown out of balance, the Avatar of that era usually represents what is missing.

Aang did not know any other elements just as the world lacked unity which caused a devastating war to drag on. So he made friends with people from the other nations and by learning the spiritual principles behind each form, Aang achieved the power to spiritbend.

Korra (to my knowledge) lacks the spiritual understanding that is demanded of the avatar. She will not likely be conversing with spirits or entering the Avatar state any time soon. Her era also lacks this spiritual balance. The speed of progress and technology has left the city cold and unsympathetic. They take things such as technology and bending for granted.

The Equalists see this imbalance, but they think the solution would be to remove bending completely. This would also destroy the spiritual aspect of the world too. All the lessons that come with bending would disappear.

Edit: Little do they know, the Equalists are also part of the problem. Their beliefs also stem from the lack of knowledge of the spiritual aspect of bending and they are also cold and unsympathetic. The most disturbing part is that despite being the ones who will attack (or execute whatever their plans are first, I'm sure it's gonna look evil), they play the victim card.